MSP430I2041: power reset

Hi,

When I program the board, everything is working fine. When I remove the power supply no character is seen on serial terminal (this is fine). When I connect the power supply , sometimes I am seeing a ',' and sometimes a blank space. I think that the device gets reset when I remove and connect the power supply. This reset affects the UART configuration. How to ensure that even after a power reset, the device functions as desired? This might have something to do with power reset interrupt but I am unable to incorporate this in my program.

Best Regards,

Abhishek.

Hi,

    I am talking about removing the usb cable. I am programming my board through the ezFET lite available on MSP430F5529LP. The usb is being used for power, programming and UART communication.

Best Regards,

Abhishek.

Hi,

No this issue is not solved yet.  What I am observing is that after every power cycle, UART is sending incorrect characters to the serial terminal. Please find the attached main.c and low_level_init.c files that I have included in my project.

main.c

#include "msp430.h"
unsigned char i;
void main(void) {
    WDTCTL = WDTPW | WDTHOLD;               // Stop watchdog timer

    P1SEL0 |=   BIT2 | BIT3;                // P1.2/3 eUSCI_A Function
    P1SEL1 &= ~(BIT2 | BIT3);

    UCA0CTL1 |= UCSWRST;                    // Hold eUSCI in reset
    UCA0CTL1 |= UCSSEL_2;                   // SMCLK
    UCA0BR0   = 0xAA;                       // 9600 baud
    UCA0BR1   = 0x06;
    UCA0MCTLW = 0xD600;                     // 16.384MHz/9600 = 1706.6667 (See UG)
    UCA0CTL1 &= ~UCSWRST;                   // Release from reset
    UCA0IE   |= UCRXIE;// Enable RX interrupt
    i='f';
while(1)
{
	while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
	                 UCA0TXBUF = i;
}
    __bis_SR_register(LPM0_bits | GIE);     // Enter LPM0
    __no_operation();                       // For debugger
}

low_level_init

#include "msp430.h"

#ifdef __TI_COMPILER_VERSION__
int _system_pre_init(void)
#elif __IAR_SYSTEMS_ICC__
int __low_level_init(void)
#elif __GNUC__
extern int system_pre_init(void) __attribute__((constructor));
int system_pre_init(void)
#else
#error Compiler not supported!
#endif
{
    unsigned long *jtagPwd = (unsigned long *)JTAG_DIS_PWD1;

    /* Feed the watchdog timer */
    WDTCTL = WDTPW | WDTCNTCL;

    /* Check JTAG password locations and disable JTAG if passwords don't match.
     * Else the JTAG will be enabled in the 64th cycle after reset.
     */
    if ((*jtagPwd != 0x00000000) && (*jtagPwd != 0xFFFFFFFF))
    {
        /* Disable JTAG */
        SYSJTAGDIS = JTAGDISKEY;
    }

    /* Calibration section
     * Check for the BORIFG flag in IFG1. Execute calibration if this was a BORIFG.
     * Else skip calibration
     */
    if (IFG1 & BORIFG)
    {
        /* Perform 2's complement checksum on 62 bytes of TLV data */
        unsigned int checksum = 0;
        unsigned char *TLV_address_for_parse = ((unsigned char *)TLV_START);
        unsigned int *TLV_address_for_checksum = ((unsigned int *)TLV_START + 1);

        do
        {
            checksum ^= *TLV_address_for_checksum++;
        } while (TLV_address_for_checksum <= (unsigned int *)TLV_END);

        checksum ^= 0xFFFF;
        checksum++;

        /* If check sum is not correct go to LPM4 */
        if (*((unsigned int *)TLV_START) != checksum)
        {
            /* Enter LPM4 if checksum failed */
            __bis_SR_register(LPM4_bits);
        }

        /* Check sum matched, now set calibration values */

        /* Calibrate REF */
        REFCAL1 = *(TLV_address_for_parse + TLV_CAL_REFCAL1);
        REFCAL0 = *(TLV_address_for_parse + TLV_CAL_REFCAL0);

        /* Calibrate DCO */
        CSIRFCAL = *(TLV_address_for_parse + TLV_CAL_CSIRFCAL);
        CSIRTCAL = *(TLV_address_for_parse + TLV_CAL_CSIRTCAL);
        CSERFCAL = *(TLV_address_for_parse + TLV_CAL_CSERFCAL);
        CSERTCAL = *(TLV_address_for_parse + TLV_CAL_CSERTCAL);

        /* Calibrate SD24 */
        SD24TRIM = *(TLV_address_for_parse + TLV_CAL_SD24TRIM);

        /* Clear BORIFG */
        IFG1 &= ~(BORIFG);
    }

    /* Feed the watchdog timer */
    WDTCTL = WDTPW | WDTCNTCL;

    /* Return value:
     *  1 - Perform data segment initialization.
     *  0 - Skip data segment initialization.
     */
    return 1;
}